# encodeBytes(_:length:forKey:) Encodes a buffer of data, given its length and a pointer, and associates it with a string key. ``` func encodeBytes(_ bytes: UnsafePointer?, length: Int, forKey key: String) ``` ## Discussion Subclasses must override this method if they perform keyed coding. ## See Also [`decodeBytes(forKey:returnedLength:)`](/documentation/Foundation/NSCoder/decodeBytes(forKey:returnedLength:)) Decodes a buffer of data that was previously encoded with [`encodeBytes(_:length:forKey:)`](/documentation/Foundation/NSCoder/encodeBytes(_:length:forKey:)) and associated with the string `key`. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)